Compositions of improved viscosity index containing alkyl polymethacrylate of high relative syndiotacticity



Feb. 14, 1967 J.E.F1E| Ds ETAL 3,304,260

IMPROVED VISCOSITY INDEX CONTAINING I COMPOSITIONS OF ALKYL POLYMETHACRYLATE OF HIGH RELATIVE SYNDIOTACTICITY Original Filed Dec. 30. 1960 5 Sheets-Sheet 1 N.. .l ON NN .VN @.N QN Od N m am INVENTORS JOSEPH E. FIELDS BY EDWARD H. MOTTUS ATTORNEY Feb. 14, 1967 1. E. FlELDs ETAL 3,304,260

COMPOSITIONS OF IMPROVED VISCOSITY INDEX CONTAINING ALKYL POLYMETHACRYLATE OF HIGH RELATIVE SYNDIOTACTICITY Original Filed Dec. 30. 1960 5 Sheets-Sheet 2 INVENTORS JOSEPH E. FIELDS EDWARD H. MOTTUS FIG.2

ATTORNEY MICRONS Www/@MW RELATIVE SYNDIOTACTICITY Feb. 14, 19

Original Filed Dec. 30. 1960 IOO 67 J. E. Flr-:LDS ETAL 3,304,260 COMPOSITIONS OF IMPROVED VISCOSITY INDEX CONTAINING ALKYL POLYMETHACRYLATE OF HIGH RELATIVE SYNDIOTACTICITY 5 Sheets-Sheet 5.

FIG. 3 sYNnloTAcrlcY FROM Dn-Flalarirslm. IR ANALAsls l. PoLY(N-| AURYL METHACRYLATE) 2. N-LAURYL METHACRYLATE/METHYL METHACRYLATE 72E/2B COPOLYMER I R VALUE INVENTORS JOSEPH E. FIELDS EDWARD H. MOTTUS ATTORNEY Feb. 14, 1967 Original Filed Dec. 30, 1960 L56 EFFICIENCY J. E. FIELDS ETAL `3,304,260

COMPOSITIONS OF IMPROVED VISCOSITY INDEX CONTAINING ALKYL POLYMETHACRYLATE OF HIGH RELATIVE SYNDIOTACTICITY 5 Sheets-Sheet 4 FIG. 4

sYNDloTAcTIc (0) 2. coNvENTaoNAL MM IN COPOLYMER 0F LM/MM INVENToRs JOSEPH E. FIELDS EDWARD H. MOTTUS BYMMW ATTORNEY vlscoslTY INDEX (il) Feb. 14, 1967 J. E. FIELDS ETAL 3,304,260

COMPOSITIONS OF IMPROVED VISCOSITY INDEX CONTAINING ALKYL POLYMETHACRYLATE OF HIGH RELATIVE SYNDIOTACTICITY Original Filed Dec. 30. 1960 5 Sheets-Sheet 5 FIG; 5

ooc sYNDloTAcTlc 'l2/2e LM/MM COPOLYMER -0- CONVENTIONAL 'l2/2B LM/MM COPOLYMER OO l l I I n n l |y l n ln l I CONCENTRATION IN OIL INVENTORS JOSEPH E. VFIELDS EDWARD H. MOTTUS BVM/(MW ATTORNEY United States Patent O This application is a divisional application of my copending application Serial No. 79,671, iiled December 30,

1960, now United States Patent No. 3,252,949.

The invention relates to highly syndiotactic oil-soluble methacrylate polymers having superior viscosity index improving properties when incorporated in mineral and synthetic oils (functional uids) and to compositions of these polymers in the functional uids. These polymers can also have dispersancy properties by incorporating a minor amount of an appropriate comonomer during polymerization to give the polymer dispersancy properties or by treatment after the formation of the polymer.

Conventional methacrylate polymers useful 4as viscosity index improvers in functional fluids are described in U.S. 2,091,627. These polymers are made by freeradical polymerization at about 70 F. or above. Recently methods of making certain stereospecic polymers have been discovered and reported; for example, a paper was presented at the April 1959 meeting of the American Chemical Society, Division of Paint, Plastics and Printing Ink Chemistry, titled, Stereospecific Anionic Polymerization of Methyl Methacrylate, by W. E. Goode et al. This paper is reported in the dvisions preprints on pages 135-140. syndiotactic, isotactic, 'block polymers and conventional polymers are described in this paper.

Also crystalline oil-insoluble polymers of methyl methacrylate and certain other monomers are known as is indicated in Belgium Patent No. 566,713. These methacrylate polymers of the Belgian patent which were made by free radical polymerizations at low temperatures of the order of 0 C. and lower are undoubtedly highly syndiotactic, but of course these polymers are oil-insoluble as will be seen in further discussion of the invention hereinbelow.

The surprising discovery has now been made that the higher the degree of syndiotacticity in methacrylate polymers the better will be the viscosity index improving characteristics of the polymer. Improved oil-soluble methacrylates having relative syndiotacticity in excess of 87 have now been made, which polymers have improved viscosity-index improving qualities as compared to the conventional methacrylate polymers. It is preferred that the relative syndiotacticity of the polymers be at least 90. The signicance of the numerical limits on relative syndiotacticity will be clear from the detailed discussion of the invention.

It is an object of this invention to provide new and improved viscosity index improving polymers.

It is another object of this invention to provide new and improved viscosity index improving polymers which also have dispersancy properties.

It is another object of this invention to provide highly syndiotactic oil-soluble methacrylate polymers having superior viscosity index improving characteristics.

It is another object of this invention to provide new and improved mineral and synthetic oil compositions having high viscosity index characteristics.

It is another object of this invention to provide new and improved mineral and synthetic oil compositions having both -hi-gh viscosity index characteristics and good dispersancy properties.

3,304,260 Patented Feb. 14, 1967 T-hese and other objects of the invention will become apparent as the detailed description of the invention proceeds.

The new polymers of the invention are made by polymerizing alkyl methacrylate having from about 6 to about 20 carbon atoms in the alkyl group by free-radical polymerization at low temperatures of the order of about 30 C. or lower, preferably 0 C. or lower. Alternatively alkyl methacrylates having from about 8 to about 20 carbon atoms in the alkyl group can be copolymerized with Cl-C, alkyl methacrylates wit-h the amount of the lower alkyl methacrylate in the copolymer being limited to insure that the copolymer is oil soluble, e.g. when a 50/50 molar mixture of methyl methacrylate and lauryl methacrylate is polymerized the resulting polymer is insolu-ble in mineral lubricating oil; whereas, if the mixture is 35/ 65 molar of methyl methacrylate and lauryl meth- -acrylate the resulting polymer is soluble in mineral lubricating oil.

In general it can be said that the average number of carbon atoms in alkyl groups of the methacrylate monomers for homopolymers as well as polymers of mixtures of monomers should be at least about 7.5 for the polymer to be soluble in mineral lubricating oil to the extent of at least 1% by weight; whereas, if the oil is a mineral or synthetic hydraulic oil having an appreciably lower viscosity than mineral lubricating oil the average number of carbon atoms in the alkyl groups can be as low as about 6.0 to about 6.5 depending on the particular oil being used. Preferred polymers have an average number of from about 6.0 to about 18 carbon atoms in the alkyl groups. For the purposes of the claims, oil-solubility is defined as the polymer being soluble at 25 C. to the extent of at least 1% in a petroleum base hydraulic iluid meeting Government specifications MIL-O- 5606. Preferred polymers have specific viscosities of a 1% solution in benzene at 25 C. in the range of about 0.4 to about 7.0, more preferably in the range of about 0.5 to about 3.0. In the claims the terms a major amount and a minor amount are used. A major amount means in excess of 50% by weight of the monomer mixture or oil composition, and a minor amount means less than 50% and obviously where there are recited two minor amounts of different monomers they must necessarily add up to less than 50%.

The alkyl methacrylates can either be straight chain alkyl or branched chain except that if it is desired to also use the methacrylate polymer as a pour point improver the alkyl group should ibe straight chain. The polymers of the invention can also be provided with dispersancy characteristics by polymerizing with the metlhacrylate monomers a minor amount of polar or hydroprilic monomers. Polar groups are groups such as OH, COOH, NH2, NHR, NR'R where the Rs are hydrocarbon lradicals which can be either substituted or unsubstituted, preferably alkyl group having up to 4 carbon atoms or cyclohexyl groups. An illustrative but non-limiting listing of such polar monomers -is as follows: vinyloxyethanol, -dimethylaminoethyl methacrylate, diethylaminopropylmethacrylamide, N-vinylpyridine, N-vinyl-Z-pyrrolidone, met-hacrylic acid, acrylic acid; ethylene-1,2-dicarboxylic acids and half esters thereof such as maleic acid, Ifumarie acids, the monoor dichloro-substituted maleic or fumarie acids, alkyflated maleic and fumarie acids, monoor diphenyl maleic acids, benzyl maleic acid, ethyl maleic acid or any similar acids containing a double bond in the chain between two carboxyl grou-ps such as mesaconic and citraconic acids, acids such as itaconic and Igl-utaconic acids, anhydrides of any of the above acids capable of anhydride for-mation which can be hydrolyzed to give :free carboxyl groups, etc.

, Alternatively, the prepared methacrylate polymers vof the invention can be partially amidated or esteried to add the polar groups by treatment with such materials as:

N,Ndimethyl-1,2-et-hylened-iamine, N-methyl-N-ethyll ,2-propylenediamine, N,Ndiet'hyl-1,3-propylenediamine, N,N-dipropyl1,3 epropyienediamine, N,N-diisopropyl41,3 -propylene diamine, N,N-dibutyl1,3 -propylenediamine, v N,N-'(ditbutyl) -1,3 -propylenediamine, N,N,Ntrimethyl-l ,3-propylenediamine, N,N4dicyclohexyl l ,3 -propylenediamine bis dimethylaminopropylene) amine, dimethylarnino-p-phenylene amine;

2- (dimethyiamino ethanol, Z-(methylethylamino ethanol,

3- dipropylamino propanol,

3 diisopropylamino propanol,

3- (dibutylamino propanol,

3 di-t-butylamino propanol,

3 (dicyclohexylamino) propanol, 4-(dimet`nylamino) butanol,

3- (diethylamino -t-butanol,

dimethyl amino-pqphenol,

etc. The polar monomer or the equivalent in partially amidated or esterified polymer should be present in the total polymer in amounts of between about 0.5 and 20% by weight, preferably about 5 .to .about 15% by weight. Minor amounts ot other comonomers can be used eg. styrene, vinyl acetate, etc., if desired, to give other desirable characteristics to the polymer.

The polymers of the invention are normally incorporated in mineral or synthetic oils to the extent of at least 0.1% by weight based on the composition of the polymer in oil and normally in amount not in excess of about except where concentrates are prepared to be blended back with oil in which case the polymer in the concentrate may be f1rom about 20% to 50% or higher. For use as viscosity index improvers usually the polymers will normally be blended in the oils to the extent of trom about 1% to about 7% by weight lbased on the oil composition, butin case vthe polymer is also a dispersant itv can be desirable to use higher than 7%.

VFor the functional huid compositions of the invention mineral base oils or synthetic base oils can be use-d. As viscosity index (VJ.) improvers or as vis-cosity index improvers and -dispersant additives, the polymers of the invention can be added to lubricating oils, diesel oils, furnace oils, lhydraulic oils, automatic transmission oils and `the like.

Depending on the particular use, it can be desirable for a functional fluid to have high viscosity index. An illustrative but non-limiting list of other functional iiuids which are improved in viscosity index and in dispersant characteristics by addition of polymers of the invention are the following: polyphenyls such as lbiphenyl, the ter- Vphenyls such as o, mand p-terphenyl and alkylated biphenyl and terp'nenyls such as the mono or dialkyl, methy-l, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, etc.; partially chlorinate-d biphenyls known in the trade as Aroclors which contain from about 40 to I80% by weight of combined chlorine; poly(oxyphenylene) benzenes and particularly ethers of the formula nu r wherein n is an integer ifrom about 3 to about 8, R is an alkyl radical having ibelow Yabout 5 carbon atoms, i.e. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl or mixtures thereof, and x is an integer Ifrom 0 to 4; diesters of dicarboxylic acids such as dioctyl sebacate and dioctyl adipate and esters such as pentaerythritol tetracaproate; phosphates such as' t-rialkyl phosphates from tributyl to trilauryi such as tri(2ethylhexyl) phosphate, dialkyl monoaryl phosphates 4wherein the alkyl groups are C4-C12 and the aryl groups are phenyl or cresyl, particularly :dibutyl phenyl phosphate an-d di(2 ethylhexyl) phenyl phosphate, the monoatlkyl diaryl phosphates wherein the alkyl groups are C24-C12 and the aryl groups are phenyl and/or cresyL especially Z-ethylhexyl `diphenyl phosphate and -methylheptyl diphenyl phosphate, the liquid triaryl phosphates, namely t-ricresyl phosphate, cresyl diphenyl phosphate and phenyl dicresyl phosphate; liquid polymeric silicones which are well known in the art; etc.

The invention will be more clearly understood from the following detailed description of speciiic examples thereof read in conjunction with the accompanying drawings wherein:

FIGURE 1 is a graph showing a number or curves of efiiciency as a viscosity index improver v. specific viscosity at 100 F. for a number of different methacrylate polymers incl-uding isotactic, conventional, and syndiotactic polymers of the invention;

FIGURE 2 is a graph showing several differential infrared curves of several syndiotactic polymers compared with an isotactic polymer;

FIGURE 3 is a graph showing two calibration curves for two different methacrylate polymers, these curves being useful for determining relative syndiotacticity from differential infrared values;

FIGURE 4 shows the effect on eiiiciency of increasing the amount of methyl methacryl-ate comonomer with lauryl methacrylate for both conventional methaerylate polymers and syndiotactic polymers of the invention; and

FIGURE 5 shows a comparison between the amount of a syndiotactic polymer of the invention required to give a certain viscosity index versus amount required for a comparable conventional methacrylate polymer.

EXAMPLE 1 This example describes the making of a 90/ 10 lauryl methacrylate/ methyl methacrylate polymer of the invention. To a glass reaction iiask was added 22.86 g. (0.09 mole) of lauryl methacrylate, 1.0 g. (0.01 mole) of methyl methacrylate and 20 ml. of dry toluene. The monomers 4and toluene were mixed and cooled in an ice bath to 0 C. The reaction mixture was blanketed with nitrogen and 0.20 ml. of triethylboron was added. The nitrogen was then displaced with air and the reaction mixture stirred occasionally with the reaction being allowed to run at 0 C. overnight. The product polymer was precipitated in methanol, dissolved in benzene, reprecipitated from methanol, and this 4sequence of purification steps Was repeated once again. The puried polymer was then dried at 50 C. in a vacuum oven overnight. Dry weight of the puriied polymer was 18.0 g. An elemental analysis of a sample of this polymer yielded the following results- Found: C, 74.1%; H, 11.4%. 11.7%.

Calcd: C, 74.9%; H,

EXAMPLE 2 This example describes the making of an 20 lauryl meth-acrylate/methyl methacrylate polymer of the invention. To the reaction vessel was charged 20.32 g. (0.08 mole) of lauryl methacrylate, 2.0 g. (0.02 mole) of methyl methacrylate and 20 ml. of dry toluene. This experiment was run by exactly the same procedure as the experiement in Example 1 with the same amount of triethylboron lcatalyst being added as it was in Example l. The yield of puried dry polymer was 11.1 g. An elemental analysis of a sample of this polymer yielded the following results- Found: C, 73.4%; H, 11.4%. 11.5%.

Calcd: C, 74.1%; H,

EXAMPLE 3 This example describes the making of-a 65/ 35 lauryl methacrylate/methyl methacrylate copolymer of the in.`

vention. This experiement was run in the same manner as was Example 1 except that the charge of monomers to the reactor was 16.51 g. (0.065 mole) of lauryl methacrylate and 3.5 g. (0.035 mole) of methyl methacrylate. A sample of 20 ml. of toluene was charged along with the monomer and the same amount of catalyst was added later as in Example l. Yield of puried dried polymer was 11.5 g. An elemental analysis of a sample of this polymer yielded the following results- Found: C, 72.2%; H, 11.0%. Calcd: C, 72.8%; H, 11.2%.

EXAMPLE 4 This example describes the preparation of an isotactic polymer from tallow methacrylate, which is a mixture of about 33% by weight of C16 and about 67% by weight of C18 straight-chain alkyl methacrylates. To the reaction vessel was charged 200 ml. of toluene at C. and nitrogen blanketing was applied. To this toluene in the reaction vessel was added the Grignard catalyst which was 3 ml. of 3 molar phenylmagnesiumbromide in ethyl ether. The tallow methacrylate monomer was purified by percolation over alumina and a sample of this puried material 31.2 g. was added to the reaction vessel over a 24 minute period at a rate to keep the temperature between 0-5 C. After four hours during which time the reaction mixture was maintained at about 0 C. the reaction mixture was poured into methanol. The crude polymer was recovered from the methanol, Vdissolved in benzene and precipitated from methanol with this purication pro-cedure being repeated two more times. The purified polymer was then dried in a vacuum oven for 58 hours. Yield of dried polymer was 22.8 g. This polymer is a solid at room temperature.

EXAMPLE 5 This example describes the preparation of a sample of conventional tallow methacrylate polymer. To a Coke bottle was charged 65.8 g. of tallow methacrylate, 44 g. of benzene and 0.082 g. of azobisisobutyronitrile catalyst. The bottle was then ilushed with nitrogen and sealed. This bottle was placed in a rotating air oven to facilitate agitating reactants and maintained at 70 C. for a period of 65 hours. The polymer product was puried in a manner similar to that described in Example 4. Yield of dried polymer was 65.5 grams.

EXAMPLE 6 This example describes the preparation of a tallow methacrylate polymer of the invention. To the reaction vessel was added 32.9 g. of tallow methacrylate and 25 ml. of toluene. The mixture of toluene and monomer was ilushed with nitrogen and 'cooled to 0 C. Next 0.29 ml. (2 mole percent) of triethylboron was added to the reaction and then 0.145 ml. (1 mole percent) of cumene hydroperoxide was added to the reaction flask. The mixture was thoroughly stirred and allowed to react -at 0 C. for 21 hours. The polymer was puried by dissolving in benzene and precipitating in methanol, repeating this procedure two more times. The purilied polymer was dried in a vacuum oven at 50 C. for 45 hours. Yield of polymer was 11.5 g.

EXAMPLE 7 This example describes the preparation of a lauryl methacrylate/methyl methacrylate/vinyloxyethanol terpolymer of the invention having both high viscosity index characteristics and dispersant properties. To the reaction ask was added 38.1 g. (0.15 mole) of lauryl methacrylate, 5.0 g. (0.05 mole) of methyl methacrylate, 4.4 g. (0.05 mole) of Z-vinyloxyethanol and 0.3 ml. of pyridine. This mixture of materials was cooled to 0 to 1 C. under nitrogen blanketing and 0.55 ml. of triethylboron was added. After the addition of the triethylboron 0.23 ml. of cumene hydroperoxide was added to the reaction mixture. Polymerization time was 4 hours during which 75 time the temperature was maintained between 1 and 6 C. At the end of the polymerization period, benzene was added to dissolve the polymer. Yield of polymer was 93% and 3.6% vinyloxyethanol (VOE) was found therein.

EXAMPLE 8 This example describes the making of a dispersant polymer of the invention wherein Lorol methacrylate, methyl methacrylate and N-vinyl-Z-pyrrolidone are the monomers. Lorol methacrylate is a mixture of methacrylates made by esterifying methacrylic acid with a mixture of 3% C10, 61% C12, 'C14, 11%-C16 and 2%-013 straight-chain alkyl alcohols. To the reaction ask was charged 38.1 g. of Lorol methacrylate, 5.0 g. of methyl methacrylate and 4.4 g. of N-vinyl-2-pyrrolidone. The mixture of monomers was then cooled to 0 C. under nitrogen, 0.28 ml. of pyridine was added, 0.53 ml. of triethylboron was added and 0.22 ml. of cumene hydroperoxide was added in the order listed to the reaction vessel. Temperatures in the reaction ask were maintained at not more than 5 C. for two hours at which time 48.6 g. of 4mineral white oil were added. Polymerization was continued for 4 more hours at the same temperatures at which time 47.2 g. additional mineral white oil were added to the reaction mixture. Then the reaction mixture was allowed to stand at room temperature for two days and the polymerization appeared complete. An additional 15.0 g. of mineral white oil were added to the reaction mixture to bring the polymer concentration to 30% by weight.

EXAMPLE 9 This example describes the preparation of a conventional polymer for comparison with the polymer of the invention of Example 8. To a Coke bott-le was charged 40.2 g. of Lorol methacrylate, 5.0 g. of methyl methacrylate, 4.2 g. of N-vinyl-Z-pyrrolidone, 32.9 g. of -benzene and Y0.156 g. of azobisisobutyronitrile. The bottle was lushed with nitrogen, sealed and placed in a rotating oven providing agitation at 68 C. for 4 days. The polymer was recovered ifrom the benzene by precipitating with methanol. Yield of the recovered polymer was 45.8 g. having 0.8% nitrogen.

EXAMPLE 10 This example describes the preparation of a polymer of the invention from Lorol methacrylate at 0 C. A 19 g. sample of Lorol methacrylate was mixed with dry toluene in a tube. The mixture was bu'bbled with nitrogen and 0.1 rnl. of triethylboron was added. The tube was kept under nitrogen and placed in a Dry-Ice acetone bath. Then 0.3 ml. of 3% H2O2 was added. The temperature of the bath was too low and Lorol methacrylate crystallized out. The reaction tube was then transferred to an ice bath. Total polymerization time at ice :bath temperatures was 21 hours. The polymer was precipitated from the reaction mixture with methanol and this polymer was further purified 'by dissolving in Ibenzene and precipitating with methanol three times. The purified polymer was dried at 50 C. in a vacuum oven overnight. The yield was 7.6 g. of dried polymer.

EXAMPLE l1 This example describes the preparation of a terpolymer of the invention at about 20 C. To a yglass reaction vessel were added 29.0 g. of oxo-tridecyl methacrylate, 20.5 g. of tallow methacrylate and 8.0 g. of methyl methacrylate, and nitrogen blanketing was applied. The designation of oxo indicates that the alkyl group is branched rather than straight chain, the alcohol thereof having been made by the well-known Oxo process. Then 0.30 ml. of pyridine and 0.55 ml. of boron triethyl were .added to the monomers and the reactor was placed in a water bath. Next 0.23 ml. of cumene hydroperoxide was added and polymerization was carried out with stirring 7 a and maintaining the temperature between 17 and .24 C. Viscosity at 210 F., centistokes 3.94 for a period of 2 hours. At the end of this time benzene Viscosity at 100 F., centistokes 21.58 was added to bring the polymer into solution and the Viscosity index 75.3 polymer was puritied in the usual manner by precipita- Speciic gravity 25 /25 C. 0.886 tion from methanol, redissolving in benzene and precipi- 5 Flash point, Cleveland open cup, F. 375 tating from methanol 2 more times. The puriiied polymer Base oil No. 2 was dried overnight in a vacuum oven giving 52.1 g. of dry polymer (905% yie1d) This O11 is a solvent rened Mid-Continent petroleum lubricatinf `l hav'n th ollowinv r e ties: EXAMPL-Eiz w @01 1g ef k a.popr

l Viscosity at 210 F., centisto es 10.39

This examples describes the preparation 0f aflspersan Vscosity at 100 F., censtokes 91.73 additive of the invention. To a glass reaction vessel VSc0s-t dex 103 4 tted with a stirrer and nitrogen inlet and Outlet Were F11 h 1 yntl C1 e-lu TFT n 45() Base all No' 1 Y 35 Viscosity at 210 F., centistokes 5,74 This is a solvent rened Mid-Continent petroleum Viscosity at 100 F., centistokes 37.23 lubricating oil having the following properties: Viscosity index 103.7

TABLE 1 Sp. Visc. in Ex. Monomers l Moiiomer, Mole Type of Polymer Benzene at Sp. Vise.2 at Sp. vise.2 at Efficiency 2* No. atie 1% Cone. 100 F. 210 F.

and C.

LM/MM- 90/10 Syndotactic 0. 299 0 415 1 39 LM/MM 80/2 .do 0.540 0.777 1 44 LM/MM 65135 -do.. 0.172 0. s 1 79 TM Isotactic- 0. 315 0. 483 0. 519 1 0g TM Conventional- 1. 793 2. 052 1 14 TM Syndiotactic. 1. 717 2. 029 1 18 LM/MM 0E 60/20/20- do 1.209 0.699 1.198 1 79 LoM/MM/VP S25/20.8007- do 0. 819 1.395 .-1 1 70 LOM/MMIV P 60.9/21.7/17.4 Conventional- 0.570 Q 851 a 1 49 LM Syndiotaetic 1. 008 1. 488 1. 874 1 25 oTM/TM/MM 43.3/24.9/3i.s (20 C.) syndiotaetie 1. 345 1.395 2.022 1 45 o'rM/TM/iiiM/VP do 1. 386 i. 90s 1 38 LM Isotactie 0. 953 1. 399 1. 413 a 1 01 0. 968 i. 421 1. 009 1 20 1. 701 2. 812 3.379 1 2@ Syndiotactic 0. 798 1. 109 1. 391 1 25 do 1.752 2. 804 s. 553 1 27 (-20 C.) Syndiotactic 0.432 0.480 0.626 1 30 1S0tae1ie 2. 280 i. 70s 2. 054 1' 20 ConventionaL 0. 622 0. 937 1: 51 do 0. 654 0.985 1 51 0. 793 1. 199 1. 51 0. 866 1. 300 1 51 1. 270 1. 966 1 55 1.905 3.124 1 59 LM/MM 2. 217 3. 48s 1 57 LM/MM 0. 548 0. S 1 60 LM/MM 0. 711 1. 1 60 1. 591 2. 612 1 64 3.461 5.993 1 73 3- 628 6. 335 1 75 0` 240 0. 376 1 57 1. 086 1. 184 1 09 0- 541 0. 828 1 53 1. 233 1. 503 1 27 1. 114 i. 541 1 35 (I). 67S1) l B 1. 1605 1 72 DSO v LM/MM 65/35 0.12611]D em iiO M 2 l 74 oTM/TM/MMNP a9.;22.9/20.s/16.7 (i689 0 953 I 1j 38 lLvI-L 1 11i 1 t MM-Meth imeth cr 1 te. TM-T 1- t t ith 1 crylate. VP-N-vinyl-Zpyrrolidone. OTM-Oxetrideeyl methacrylate.

2 These specific viscosities and efficiencies were determined from a 30% 3 These specic viscosities and eti'ciencies were determined from a 30% In Table 1 above is contained a summary of Examples l-12 and the viscosity index improving characteristics of the polymers of these examples. In adition are summarized a number of other examples of polymers which were used to obtain data for the gures or for other purposes later discussed.

The experiments of Examples 13-40 were carried out in an analogous fashion to corresponding isotatic, conventional or syndiotactic Examples 1-12. Under the column titled Type of Polymer in Table 1 all syndiotactic polymers were made at about C. except as indicated diiferently, i.e. (20 C.) Syndiotactic means the polymer was made at about 20 C. and (-20 C.) syndiotactic means the polymer was made at -20 C. In general the Type of Polymer has been determined qualitatively by the method ofr making the polymer, but also a number of the polymers have been subjected to infrared analysis (to be distinguished from differential infrared analysis later discussed). Isotactic or syndiotactic polymers have their own characteristic infrared patterns. Eiiiciency is a measure of the viscosity-temperature coetiicient of a polymer in the solvent in which the measurements are made.

specific viscosity at 210 F. EmmenCy-specie viscosity at 100 F.

In general the higher the efficiency the higher is the viscosity index.

The curves of FIGURE 1 are plotted from data found in Table 1. Abbreviations used in the key of FIGURE 1 have been previously defined in Table 1 and detailed experimental examples. Eiiiciency as a viscosity index improver is plotted in this figure versus the specific viscosity of the polymer at 100 F. Using lauryl methacrylate as a monomer, samples of isotactic polymer, samples of conventional polymer, .samples of highly syndiotactic polymer prepared at 0 C. and samples of very highly syndiotactic polymer prepared at 20 C. were made. From a different monomer system namely lauryl methacrylate/methyl methacrylate in a molar ratio of 72/ 28 respectively, samples of isotactic, conventional and 0 C. syndiotactic polymers were prepared. If the curves for polylaurylmethacrylate are examined, it is seen that that least eicient polymers are the isotactic and the most etiicient are the most syndiotactic. The same conclusion is reached if the curves of lauryl methacrylate/methyl methacrylate polymers are examined. Furthermore, it can be concluded that there is a tremendous difference in the eiciency between the isotactic and the highly syndiotactic polymers. Conventionaloil-soluble methacrylate polymers are predominantly syndiotactic but are appreciably less syndiotactic than the polymers of the invention. It appears that the higher the syndiotacticity the greater is the eiciency. Thus the highly syndiotactic polymers of the invention are appreciably improved over the conventional polymers as to eiciency.

Among the different ways in which the polymers were compared was by the use of a differential infrared spectrometer. In FIGURE 2 are shown three curves of infrared spectra resulting from a comparison of 3 diierent polymers with a standard isotactic polymer. The samples were each dissolved to a concentration of in a mineral white oil. A standard sample against which all samples were compared for the gure was the isotactic polymer of Example 19. Against this isotactic polymer were compared a sample formed by mixing 30 parts of the isotactic polymer with 70 parts of the polymer of Example 32. Curve 1 is a diiferential infrared curve resulting from a comparison of the mixed polymer with the isotactic polymer. Curve 2 results from a `comparison of the conventional polymer of Example 25 with the isotactic polymer of Example 19, and curve 3 results from a comparison of the isotactic polymer of Example 19 with the syndiotactic polymer of Example 32. These curves of FIGURE 2 are merely exemplary of similar curves which are obtained with other polymers. The abscissas of FIG- URE 2 are wave length in microns. The ordinates of FIGURE 2 for the various curves are staggered so the curves can be more easily compared one with the other. The ordinates of the curves merely represent the intensity of the infrared light as recorded in the spectrometer after passing through the samples and being compared.

FIGURE 3 represents a chart for determining relative syndiotacticity from differential infrared values for two different polymers, one being a poly-lauryl methacrylate polymer and the other a copolymer of lauryl methacrylate and methyl methacrylate in molar ratio of 72/28. The two polymers used to obtain the polymer blend from which the calibration charts were made for the polylauryl methacrylate polymer are the polymers of Examples 13 and 18 and the polymer of Example 13 has been assigned a relative isotacticity of or a relative syndiotacticity of 0 and the polymer of Example 18 has been assigned a relative syndiotacticity of 100 or a relative isotacticity of 0. The polymers used for making copolymer calibration curve 2 are the polymers of Examples 19 and 32, and these polymers have been assigned relative syndiotacticities of 0 and 100, respectively, and the reverse in relative isotacticity. These polymers were then subjected to differential infrared analysis as described above with relation to FIGURE 2 and the results of these experiments are shown below in Tables 2 and 3. As in FIG- URE 2 the comparison was always made versus the isotactic sample. After carefully examining the differential infrared spectra of a large number of different polymers, two different pairs of peaks and valleys were picked as significantly indicative of the amount `of syndiotacticity in the polymers. These pairs were the peak 9.05 and the valley 9.40 pair and the peak 13.1 and the valley 13.38 pair. Thus the infrared intensity recorded at 9.05 minus that at 9.40 was one measurement and the infrared intensity recorded at 13.1 microns minus the intensity at 13.38 microns gave the other measurement. The total differences were the sum of these two in each case. These data are plotted in Table 2 below for the poly-(lauryl methacrylate) polymer.

TABLE 2 Ex. 18.1 9.05-040g 13.1-13.38p Total (Syndio- Difference Difference Difierence tactielty) 1 This column represents the percent by Weight of Example 18 polymer 1n mixtures of Example 18 and Example 13 polymers.

1 1 acrylate copolymer calibration curve were obtained and plotted in curve 2 of FIGURE 3.

TABLE 3 Ex. 32 l S05-9.4014 13.113.38p Total (Syndio- Diterence Difference Difference tacticity) l This column represents the percent by Weight of Example 32 polymer in amixture of Example 32 and Example 19 polymers.

This calibration curve 2 is then suitable for determining the relative syndiotacticity of an unknown 72/ 28 molar copolymer of lauryl methacrylate and methyl methacrylate from differential infrared analysis.

Differential infrared analysis were made comparing the isotactic polymer of Example 13 with the conventional polymer of Example 14 and comparing the isotactic polymer of Example 19 with the conventional polymer of EX- `ample 25. Then using curve 1 `of FIGURE 3 for the first pair and curve 2 of FIGURE 3 for the second pair, relative syndiotacticities were determined. The conventional poly(nlauryl)methacrylate of Example 14 was found to have a relative syndiotacticity of 83.5 and the conventional n-lauryl methacrylate/methyl methacrylate 72/ 28 copolymer of Example 25 was found to have a relative syndiotacticity of 82. These values of relative syndiotacticity for conventional oil-soluble methacrylates are a little higher but approximately the same as reported in the literature for conventional methyl methacrylate polymers.

Relative syndiotacticity limits for the claims are defined in an analogous fashion as they were for FIGURE 3, i.e. each different type of polymer such as poly (tallow methacrylate) or different copolymer would require its own calibration curve to determine accurately the amount of relative syndiotacticity. The polymer made at -20 C. by the free-radical catalysis is assigned 100 relative syndiotacticity or a relative isotac'tieity of 0, and the polymer made at about 0D C. using the Grignard catalyst is assigned the number 0 relative syndiotacticity or a relative isotacticity of 100. From differential infrared analysis of blends of these samples, a calibration Curve can be plotted which curve is useful in determining the degree of relative syndiotacticity of analogous polymers of unknown relative syndiotacticity.

In FIGURE 4 are shown two curves, one for syndiotactice polymers and the other for conventional polymers wherein efficiency is plotted versus the percent methyl methacrylate in copolymers of lauryl methacrylate and methyl methacrylate. Abbreviations used in this figure have been previously defined in Table 1. It is indicated from this curve that the higher the percentage of methyl methacrylate in the copolymers the higher will be the efficiency of the polymer; however, the higher the percentage of methyl methacrylate in the copolymer the less soluble is the copolymer and a 50/ 50 copolymer is completely insoluble in mineral lubricating oil. It is seen from this curve that the comparable syndiotatic polymers as compared to the conventional polymers have in each case higher efficiencies. The data for FIGURE 4 are contained in Table 4 below.

TAB LE 4 Mole Percent MM in Copolymer Example No. Efficiency 0 C. Syndiotactic 1MM stands for methyl methaerylate. 2 This value was taken trom a curve in Figure 1.

The efciencies of Table 4 were determined from a 30% concentrate of the polymer in Base oil No. 1 diluted to 3% polymer in Base oil No. 2.

In the curves of FIGURE 5 are illustrated one ofthe main advantages of the polymers of the invention over comparable conventional polymers. Abbreviations have been previously defined in Table l. It is customary in blending additives into lubricating oils to add a sufficient amount of the additive to produce a given viscosity index. It is clearly indicated from FIGURE 5 that an appreciably larger amount of conventional polymer will be required to blend to a certain viscosity, say 130 viscosity index as compared to the amount of syndiotactic polymer required. Thus an appreciable savings in cost of additives is made by using the syndiotactic polymer rather than the conventional. The data used to plot the FIGURE 5 curve are contained in Table 5.

TAB LE 5 Example Centistokes Centistokes Percent Viscosity N o. at 100 F. at 210 F. Polymer Index in Oil 0 C. Syndiot-actic Conventional 1 These are not the results of experimentally measured viscosities bu are rather calculated from values taken from viscosity curves oi tht experimental data.

The viscosities in Table 5V abovewere determined from a 30% concentrate of the polymer in Base oil No. 1 diluted to the percent polymer in oil shown by adding Base oil No. 2.

It was desired to see the effect of the polymers of the invention as viscosity index improving additives in different types of base oil. Therefore, blends to 3% concentration in oil were made up of one of the syndiotactic polymers of the invention in a parafiinic oil, a naphthenic oil and in an oil which was a mixed blend o-f parafdnic and naphthenic oil. Data for these tests are shown in Table 6. Also shown in Table 6 is the effect of a comparable conventional additive in the different base oils.

TABLE 6.-EFFECT OF BASE OIL ON V.I. AND EFFICIENCY Specific Viscosity Base Oil BaseIOil Eciency V.1.

' at 100 F. at 210 F.

3% in Oil of Ex. 28 (Syndiotactie LM/MM 72/28) Polymer Paralinio (Base Oil No. 4) 103. 7 0.944 Naplithenic (Base Oil No. 3) 68.4 0.841 Mixed (Base Oil No. 2) 103.7 0.711

Paraffinic (Base Oil No. 4)

A particularly important characteristic of the syndiotactic polymers of the invention is their low deposit formation as measured in the Panel Coker test. The standard Panel Coker test is described in reports of the Fifth World Petroleum Congress. In this report a model B Panel Coker is described. The Panel Coker actually used in the tests was a model C which has motor and spinning shaft mounted horizontally instead of slanting. Also the shaft and side air holes were sealed offs to prevent stray air currents and the introduction of air was provided via a needle inserted through the Teilon shaft seal. Running conditions were as follows:

In this test the oil being tested is splashed up against a hot panel. The deposit forming tendencies of the oil are then measured at the end of the testing time by weighing the amount of deposit on the panel. A summary of these tests comparing a viscosity index improver of the invention with an isotatic V.I. improver and a conventional V.I. improver are as follows:

TABLE 7.-PANEL COKER TESTS OF LM/M'NI 72/28 POLYME RS 1 Example No. Type of Polymer Panel Deposits,

Milligrams Isotactic 154. 5 Conventional 33. 7 Syndiotaetio 5. 3

1 The polymers were copolymers of lauryl methaerylate and methyl methacrylate in molar ratio of 72/28, respectively.

An examination of the data in Table 7 above indicates that the syndiotactic polymers of the invention tend to form very appreciably smaller amounts of the deposits than do the conventional and isotactic polymer. The Panel Coker tests are an indication of how a lubricant oil additive will be likely to perform in an internal combustion or diesel engine.

Table 3 below sets forth data of the testing of dispersant additives of the invention in a carbon black dispersion test. This method tests the ability of the additives to hold carbon black dispersed in kerosene. The testing is carried out both in the presence of and in the absence of water since some additives tend to leach out and become ineifective in the presence of water. A carbon black concentrate is made up to by Weight of carbon in a highly refined mineral white oil. One gram of this carbon paste is added to a by 150 mm. culture test tube with a plastic closed top, and to the flask are then added g. of kerosene. Thus, the concentrate of carbon based on the kerosene presence is 0.5% by weight. Then 0.5% by weight based on the active ingredients present of the various dispersants to be tested are weighed into separate test tubes, containing the kerosene and carbon black. The test tube is sealed and the ingredients dispersed by 15 minutes of shaking by hand. To the test, wherein water is present, 1 volume percent of water (about 0.4 ml.) is added to the other ingredients in the test tube. The test tubes after being thoroughly agitated are placed in arack and observations of the degree of settling are made periodically. The results in Table 8 are reported in the time for complete settling, the time when partial settling was observed, or the number of days that the testing was run before it was terminated when no settling was observed. The tests were conducted at room temperature.

TABLE 8.-CARBON BLACK DISIERSION Weight, Time for Carbon Time for Carbon Additive Percent Black to Settle- Black to Settle- No Water Present 1 Water Present None (JS-5 minutes. CS-5 minutes.

0.5 NS-14 days CS-24 hours. 0. 5 NS-14 days CS-4 days. 0.5 NS-21 days 0.5 NS-lO days PS-12 days- 1 N S-Not Settled. PS-Partly Settled. CS-Completely Settled.

In Table 9 below the viscosity index improving eifect of polymers of the invention in a number of different types of functional uids are shown.

TABLE 9.-VISCO.SITY INDEX EFFECT INAFUNCTIONAL FLUIDS Kin. Viso., es. No. Composition V.I.

Mineral oil hydraulic fluid 3. 81 1. 45 126. 9

MIL-O-5606) No. 1 plus 3% polymer of 11. 25 4.10 252. 4

Example 40.1 No. 1 plus 3% polymer of 10:05 3. 82 256. 0

Example 34.1 No. 1 plus 3% polymer of 8. 54 3. 49 260. 4

Example 39. No. 1 plus 2% polymer of 17. 28 8.09 202. 5

Example 38.2 Dibutyl phenyl phosphate. 4. 23 1. 51 109. 3 No. 6 plus 3% polymer of 7. 91 3. 48 272. 6

Example 39. No. 6 plus 3% polymer of 45.37 20.19 167.4

Example 38.2 10% by Wt. tricresyl phos- 19. 21 2. 55 -248. 8

phate plus by wt. Aroclor 1242.t3 10 No. 9 plus 3% polymer of 66. 5 9. 74 127.8

Example 34.1 11 No. 9 plus 3% polymer of 68. 6 10. 07 128. 9

Example 40.1 12 Pentaerythritol tetracaproate. 19. 39 4.13 134. 0 13 No. 12 plus 3% polymer of 41.35 9.29 161. 5

Example 34.1

1 Polymer concentration is on a pure polymer basis, but the polymer was added to the functional uid as a 30% concentrate in Base Oil No. 1.

2 This is an isotactic polymer and not a polymer of the invention.

2 This is a partially chlorinated blphenyl.

' of other different types of functional uids.

Thus it is seen from the data of Table 9 that the polymers of the invention are not only useful in mineral Oils 'as viscosity index improvers but also in a large number Composition No. and No. 8 althou-gh not involving a polymer of the invention demonstrates the solubility in a phosphate and a mineral hydraulic oil of a polymer that is not soluble in mineral lubricating oil, and polymers of the invention -behave similarly.

In addition to the polymeric additives of this invention, auxiliary additives can also be used in conjunction with the functional huid compositions of the invention. For example, in the case of mineral lubricating oils such additives include color stabilizers such as alkyl amines, e.g. tri-n-butyl amine or 2,4,6-tri(dimethylaminoethyl) phenol; metal deactivators, e.g. 1,2-diaminopropane; antioxidant, corrosion inhibitors and the like.V `Other additives include pour point depressant such as the Acryloids, -antifoaming agents such as silicone polymers, corrosion, friction, and oxidation inhibitors, e.g. alkyl phenols, alkyl phosphates, and salts thereof, blooming agents, metal containing detergents, and the like. The polymeric additives can also be used when they have low temperature detergency properties supplementary to high temperature detergents such as for example, barium sulfonates, barium P255 hydrocarbon reaction products, etc. These auxiliary additives may be used in amounts varying from about 0.05% to about 5% by Weight or higher. Actually if a mixture of straight-chain alcohols is used to make the methacrylic monomers, the polymer made therefrom Will in addition to having high viscosity index characteristics also be useful as a pour point depressant.

Although the invention has been described in terms of specified embodiments-Which are set forth in considerable detail, it should be understood that this is by Way of illustration only and that the invention is not necessarily limited thereto, since -alternative embodiments and operating techniques Will become apparent to those skilled in the art in view of the disclosure. Accordingly modikications are contemplated which can be made without departing from the spirit of the described invention.

What is claimed is:

1. A composition of high viscosity index comprising a major amount of ami-neral oil and at least 0.1% by weight based on said duid of an oil-soluble alkyl polymethacrylate having a relatively syndiotacticity of at least 87, and from about 6 to 20 Vcarbon atoms in the alkyl group.

2. A composition of claim 1 wherein said uid is a petroleum base mineral llubricating oil.

3. A composition of claim 2 wherein said polymethacrylate has a relative syndiotacticity of at least 90.

4. A mineral oil composition of high viscosity index com-prising a major amount of synthetic lubricating oil and at least 0.1% by Weight based on said oil of an oilsoluble alkyl polymethacrylate having a relatively syndiotacticity of at least 87 and from about 6 to about 2O carbon atoms in alkyl group.

16 5. A mineral oil composition of high viscosity index comprising a major amount of imineral oil and at least 0.1% by weight `based on said oil of an oil-soluble polymer having a relative syndiotacticity of at least 87 comprising a mixture of C-CZO alkyl methacrylate and an amount of C1-C4 alkyl methacrylate insuflicient to form an oil-insoluble polymer.

6. A mineral oil composition of high viscosity index characterstics comprising a Amajor amount of mineral oil and at least 0.1% by Weight based on said oil of an oil-soluble polymer having a relative syndiotacticity of at least 87 comprising a major amount of a mixture of oxotridecyl and tallow 4rnethacrylates and a minor amount of methyl methacrylate.

7. A mineral oii composition of high viscosity index comprising a major amount of mineral oil and at least 0.1% by Weight based on said oil of an oil-soluble polymer of a lmixture of C10-C13 straight-chain alkyl methacrylates and having a relative syndiotacticity of at least 87.

8. A mineral oil composition of high viscosity index comprising a major amount of mineral oil and at least 0.1% by weight based on said oil of an oil-soluble polymer having a relative syndiotacticity of a least 87 comprising a major amount of lauryl methacrylate and a minor amount of methyl methacrylate.

9. A mineral oil composition of high viscosity index comprising a major amount of mineral oil and at least 0.1% by Weight based on said oil of an oil-soluble polymer having a relative syndiotacticity of at least 87 comprising a major amount of a mixture of C10-C18 straightchain alkyl methacrylates and a minor amount of methyl methacrylate.

10. A mineral oil composition having high viscosity index characteristics and -dispersant properties comprising a major amount of mineral o-il and at least 0.1% by weight based on said oil of an oil-soluble polymer having a relative syndiotacticity of at least 87 comprising a major amount of a mixture of oxo-tridecyl and tallow methacrylates, a minor amount of methyl methacrylate and a minor amount of N-vinyl-Z-pyrrolidone 11. A minera-l oil composition having high viscosity index characteristics and dispersant properties comprising a major amount of mineral oil and at least 0.1% by Weight based on said oil of an oil-soluble polymer having a relative syndiotacticity of at least 87 comprising a major amount of mixture of ClrCls straight-chain alkyl methacrylates, a minor amount of methyl methacrylate and a minor amount of N-vinyl-Z-pyrrolidone.

References Cited by the Examiner UNITED STATES PATENTS 8/1938 Bruson 252-56 X 7/1964 Bayer 44-62 

11. A MINERAL OIL COMPOSITION HAVING HIGH VISCOSITY INDEX CHARACTERISTICS AND DISPERSANT PROPERTIES COMPRISING A MAJOR AMOUNT OF MINERAL OIL AND AT LEAST 0.1% BY WEIGHT BASED ON SAID OIL OF AN OIL-SOLUBLE POLYMER HAVING A RELATIVE SYNDIOTACTICITY OF AT LEAST 87 COMPRISING A MAJOR AMOUNT OF MIXTURE OF C10-C18 STRAIGHT-CHAIN ALKYL METHACRYLATES, A MINOR AMOUNT OF METHYL METHACRYLATE AND A MINOR AMOUNT OF N-VINYL-2-PYRROLIDONE. 